According to Peter Drucker, in his book Post-Capitalist Society, “Every few hundred years in western history . . . we cross a divide. Within a few short decades, society rearranges itself—its world view, its basic values, its social and political structures, its key institutions. Fifty years later, there is a new world. And the people born then cannot even imagine the world in which their grandparents lived and to which their own parents were born.”

Changes in family structure over the last fifty years clearly demonstrate this world in transition. For example, the first- time marriage rate is at an all-time low, and over half of all first marriages are preceded by cohabitation (living with a romantic partner without being married). Indeed, since 1960, the number of cohabiting couples increased by nearly 1,000 percent. Moreover, the divorce rate has increased nearly...